Which 20 prospects stood out in AFL play?

Harper, Ackley, Montgomery top list of standouts in fall action

By Jonathan Mayo / MLB.com

The 19th Arizona Fall League season has come to a close. As history has shown, many of this year's AFL participants will be hitting the big leagues in 2011 and beyond.

But just how good is this crop of talent? Scouts will always have differing opinions, and this year is no different. Some love the AFL Class of 2010; others feel it was a down year, particularly when compared to last year's group.

The following top 20 is a compilation, taken from conversations with scouts who followed the Fall League closely this season. Anyone who participated in the league was eligible for the list, even if they technically are no longer prospects (having lost rookie eligibility). Several factors were included in determining the final order, with an eye toward combining the prospect's status and upside with his performance in the league this fall.

1. Bryce Harper, OF, Washington Nationals: Playing just twice a week, the No. 1 pick from the 2010 Draft made quite an impression, creating a buzz with his plus-plus power, his plus arm in right field and his surprisingly strong running skills.

2. Dustin Ackley, 2B, Seattle Mariners: For a guy who looked lost at the beginning of the Major League season, Ackley seemed to have it all figured out in the AFL, as he led the league in a host of offensive categories.

3. Mike Montgomery, LHP, Kansas City Royals: Montgomery threw just three regular outings -- two good, one awful -- but he
also started the Rising Stars Game and continued to show the stuff that has made him perhaps the top left-handed pitching prospect in baseball.

4. Manny Banuelos, LHP, New York Yankees: Banuelos also started the Rising Stars Game, creating quite a buzz and impressing scouts with his now-plus fastball and outstanding changeup.

5. Brandon Belt, 1B, San Francisco Giants: Perhaps no hitting prospect raised his profile more during the 2010 season than Belt, and he kept it going during the Fall League, with many observers convinced he has the chance to soon be a very good everyday first baseman in the big leagues.

6. Eric Hosmer, 1B, Kansas City Royals: After a long, breakout season that included a stint with Team USA, 2008 first-rounder Hosmer ran out of gas a bit during AFL play, though he did finish the fall season with a three-hit game. Scouts still loved his approach and his swing at the plate.

7. Jeremy Jeffress, RHP, Milwaukee Brewers: An abundance of power arms was a strength of this AFL crop, and Jeffress was the best of the bunch, hitting triple-digits often, even in the Rising Stars Game. Command's still an issue, but he's got "future closer" written all over him.

8. Ben Revere, OF, Minnesota Twins: After taking part in the Futures Game and making his Major League debut in 2010,
Revere continued to make his case as a future leadoff hitter in the AFL, showing off his plus speed (13-for-13 in steals),
good reads in center and improved discipline at the plate.

9. Casey Kelly, RHP, Boston Red Sox: Kelly's AFL stint was brief -- 16 innings over four outings and 16 innings -- but as
with his regular season, scouts looked past the less-than-stellar numbers and came away very impressed by the young right-handers's stuff.

10. Jose Iglesias, SS, Boston Red Sox: How many players are worth the price of admission just to watch them
play defense? Iglesias has Gold Gloves in his future, and he's far from a zero with the bat.

11. Derek Norris, C, Washington Nationals: Norris rebounded from an injury-interrupted season and continued to show excellent on-base skills, along with some pop. He still needs work on receiving, but his plus arm allowed him to
throw out better than 46 percent of would-be basestealers this fall.

12. Charlie Culberson, 2B, San Francisco Giants: Some scouts are still dubious, wanting to see him perform again in 2011 after two so-so years in the South Atlantic League and one good season in the California League. Still, Culberson more than held his own against advanced competition in AFL play, and some scouts really believe in his bat.

13. Sammy Solis, LHP, Washington Nationals: The 2010 second-rounder was making his professional debut, more or less, in the AFL (having thrown just four innings in the South Atlantic League), and scouts came away impressed with his size, stuff and command. It wasn't much of a surprise that he was chosen to start the championship game for Scottsdale.

14. Chris Carpenter, RHP, Chicago Cubs: Carpenter's overall results weren't great, but keep in mind he had thrown 134
2/3 innings during the season. Another of the large crop of impressive power arms, he reached triple-digits in the Rising Stars Game.

15. Rex Brothers, LHP, Colorado Rockies: Brothers is yet another power pitcher, but he throws from the left side. With a fastball up to 95 mph and an above-average breaking ball, some improvement in his command could have him ready for the back end of a big-league bullpen soon. Think Mike Stanton (the reliever, not the outfielder).

16. Danny Duffy, LHP, Kansas City Royals: It has been a roller-coaster year for Duffy, but the ability is still
definitely there. He was surprisingly hittable in the spring, but the lefty still got plenty of swings-and-misses, and scouts graded his stuff highly.

17. Jason Kipnis, 2B, Cleveland Indians: All Kipnis does is hit. He had success at the plate at two levels during the regular season, and then a third -- Triple-A -- in the playoffs. After a slow start in Arizona, he came on strong with six consecutive multi-hit games to bring his numbers up. He's still a work in progress at second, but most think he'll get there.

18. Devin Mesoraco, C, Cincinnati Reds: There was some debate over which backstop had more upside, Norris or
Mesoraco, with some convinced the Reds prospect has a better chance to be an everyday, all-around catcher in the big
leagues. That said, he didn't perform as well on either side of the ball -- hitting or throwing -- this fall, though it was an admittedly small sample size.

19. Marc Rzepczynski, LHP, Toronto Blue Jays: Technically, Rzepczynski is no longer a prospect because of the 63 2/3 innings he pitched in the big leagues this year, but it was impossible to look past the lefty who topped the AFL in ERA (1.16), was fourth in strikeouts and held hitters to a .214 average.

20. Eduardo Escobar, SS, Chicago White Sox: Escobar's a bit of a sleeper pick to finish off the list, but he is an off-the-radar type who definitely helped himself with strong Fall League play. A plus defender who can flat-out run, he showed some facility with the bat that could mean the White Sox have an intriguing shortstop prospect on their hands.

Jonathan Mayo is a reporter for MLB.com and writes a blog, B3. Follow @JonathanMayoB3 on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.